Method and device for the industrial thermal treatment of elongated mechanical parts

ABSTRACT

A device for the thermal treatment of elongated mechanical parts including an oven having a cylinder barrel arranged into a heated enclosure, the barrel having at least one ring driven in rotation around an axis of axial symmetry of the cylinder barrel by a driving mechanism. The ring including at least one storage pipe parallel to the axis of axial symmetry able to receive at least one mechanical part to be heated, and the enclosure having an inlet and an outlet for the mechanical parts which are equidistant from the axis of axial symmetry for each ring of the barrel. A method for the thermal treatment of mechanical parts is also provided.

BACKGROUND

1. Technical Field

The present disclosure relates to a device and a method for the industrial thermal treatment of elongated mechanical parts, and more particularly of springs.

2. Description of the Related Art

Usually, springs are produced from a manufacturing unit in the form of a linear strip, and are then cut out from this linear strip at the length desired. They must then be subjected to a step of thermal treatment by being heated at a determined temperature for a determined duration before being packaged in transport tanks.

The document FR 1 598 224 describes a first device provided in particular with a heating enclosure. The heating enclosure comprises a conveyor cylinder barrel with equidistant radial cells, i.e., cells directed according to the radius of the barrel, and opening onto the periphery of the barrel.

In addition, the barrel does a jerky rotation movement. It then receives from the upstream side of the enclosure a cold mechanical part in an empty cell and the barrel starts turning so that the cold part is heated during its rotation. Eventually, on the downstream side of the enclosure, the barrel ejects the heated mechanical part after a rotation of around half a turn of the barrel.

This first device therefore meets the needs by authorizing heating a mechanical part. However, it has the drawback of being able to heat mechanical parts only on half a turn, which does not optimize the production rate. Now, this aspect is fundamental since production rates are very significant and they are comprised between 20,000 and 40,000 springs an hour for example.

In addition, it is to be noted that all the mechanical parts will be subjected to a thermal treatment, even if some mechanical parts are faulty.

The document GB 1 151 134 describes a second device provided with a heating enclosure wherein a cylinder barrel with equidistant axial through-cells is arranged. Each cell therefore opens onto the upstream and downstream bases of the cylinder barrel.

In addition, the heating enclosure comprises an inlet on its downstream side and an outlet on its upstream side, metal parts entering the enclosure through a side and exiting the enclosure through the opposite side.

More precisely, a first metal part falls from a funnel into a rotating picking machine which then turns of half a turn. The picking machine then lets the first metal part fall into one receptacle and receives a second metal part in another cavity thereof.

The first metal part is then pushed by a cylinder so as to enter an empty cell of the barrel via the inlet of the enclosure.

From now on each cell may contain only one metal part at a time, the whole device being exclusively provided to that end.

The barrel is then driven in rotation in a single direction by an engine. When the cell containing the first metal part faces the outlet, a second cylinder pushes this first part out of the enclosure, the first part falling into a receptacle once it has passed through the outlet.

This second device is obviously efficient. However, production rates are limited since only one metal part can be inserted into an axial cell and any other operation is impossible.

In addition, the cell of the barrel facing the outlet is separated from the cell facing the inlet by one third of the cells. Once a cell is empty, it will therefore not be immediately filled in, which limits even more the production rate.

Eventually, when they exit the enclosure, the metal parts fall into a receptacle, which does not facilitate their future packaging.

BRIEF SUMMARY

Embodiments of the present invention provide a device and a method for the thermal treatment of mechanical parts such as springs, allowing the limitations described above to be avoided, by authorizing in particular high industrial manufacturing rates and facilitating the future packaging of mechanical parts.

According to one embodiment, a device for the thermal treatment of elongated mechanical parts such as springs comprises an oven provided with a cylinder barrel arranged into a heated enclosure, the barrel comprising at least one ring driven in rotation around an axis of axial symmetry of the cylinder barrel by a driving means. In addition, the ring has at least one storage pipe parallel to the axis of symmetry able to receive at least one mechanical part to be heated, the enclosure having an inlet and an outlet for the mechanical parts which are equidistant from the axis of symmetry for each ring of the barrel. Advantageously, the first ring comprises a plurality of storage pipes arranged on its periphery and equidistant from one another.

This thermal treatment device is noteworthy in that it is provided with at least one slender hollow conveyor pipe for the mechanical parts to guide the mechanical parts toward a storage pipe to be filled in via the inlet of the enclosure according to a filling axis parallel to the axis of symmetry of the barrel and therefore the ring. The mechanical part is therefore axially transported toward an axial cell of a ring, in this case an axial storage through-pipe; the storage pipe may contain at least one mechanical part. In addition, the device comprises at least one slender hollow ejection pipe of the mechanical parts to guide the mechanical parts when they exit the storage pipe of the barrel through the outlet after a predetermined rotation of the barrel, the inlet and outlet being arranged on a same upstream side of the heated enclosure perpendicular to the axis of symmetry of the barrel.

The mechanical parts therefore enter a storage pipe according to a filling axis parallel to the axis of symmetry of the barrel and the storage pipe, via an inlet. Likewise, they exit it according to an ejection axis parallel to the filling axes.

Instead of falling into a receptacle where they may tangle, the mechanical parts are then transported toward a packaging machine which will allow them to be arranged with care into storage trays provided to that end. However, it may be provided to let the mechanical parts fall into a receptacle, if they do not require a strict packaging, instead of transporting them toward a packaging machine.

In addition, the inlet and outlet are arranged so that they are equidistant from the axis of symmetry on a same upstream side of the enclosure. This very particular arrangement allows the dimensions of the production line to be limited by sending the mechanical parts in a direction opposite to their incoming direction and not the opposite.

According to one embodiment, the oven comprises a plurality of coaxial rings, the oven being thus provided with an outlet, an inlet, a conveyor pipe and an ejection pipe for each ring arranged on the same upstream side of the enclosure.

So as to limit the costs for the installation of the device, a same oven therefore has several rings, three for example, each ring being intended for a particular type of mechanical part. As far as springs are concerned, different rings may be provided according to spring diameters, for example a first ring may be provided for five-millimeter-diameter springs and a second ring for fourteen-millimeter-diameter springs. Admittedly, the first ring will have storage pipes with a diameter that is smaller than those of the second ring.

According to the nature of the metal parts intended for being heated in the various rings, the rings depend on one another. In some embodiments, they are then actuated by a single driving means, the rotation of a ring causing the rotation of another ring.

On the other hand, in other embodiments, the rings will be independent and driven by their own driving means. This variation is particularly useful if the heating times of the mechanical parts of a ring differ from the heating times of the mechanical parts of another ring.

In addition, the device advantageously comprises a first air injection means so that the air pushes the mechanical parts from a conveyor line toward the storage pipe via a conveyor pipe. This first air injection means may be the one allowing the mechanical parts to be transported from their manufacturing unit to the conveyor pipe.

Likewise, in some embodiments, the device comprises a second air injection means so that the air pushes the mechanical parts from the storage pipes toward the ejection pipe of the corresponding ring, the second air injection means being arranged on a downstream side of the enclosure, opposite to its upstream side. The second injection means also allows the heated mechanical parts to be propelled from the ejection pipe toward a possible packaging machine passing through an ejection line.

Advantageously, the device is provided with picking means to sequentially fill in said at least one storage pipe of a ring.

According to a first variation, filling in is performed by unit. The picking means fills in a storage pipe of a ring by sending the mechanical parts to it one after another, until the storage pipe is full. Then, the barrel turns until it has an empty storage pipe in front of the inlet for a new filling.

According to a second variation, filling in is performed by batch. The picking means blocks the mechanical parts in the conveyor pipe until it contains all the mechanical parts that must enter the empty storage pipe. Then, it frees all the mechanical parts and fills in the storage pipe at once.

Preferably, the picking means comprises two electromagnets, arranged on the conveyor pipe, which operate alternately, the downstream electromagnet being in the blocking position when the upstream electromagnets is the open position, and conversely.

According to a first and a second embodiments, so as to save time, the device is advantageously provided with a sorting means so as not to thermally treat faulty mechanical parts. The faulty mechanical parts are then detected using means for visually detecting defects of a mechanical part upstream from the conveyor pipe, a camera for example.

According to one embodiment, the sorting means comprises a discard orifice for each ring arranged on the upstream side between the inlet and the outlet of the ring, the discard orifice, inlet and outlet being equidistant from the axis of symmetry.

A complementary air injection means is for example used to eject a faulty mechanical part through the discard orifice, the complementary air injection means blowing air through the downstream side of the enclosure, opposite to the upstream side.

Concretely, according to one embodiment, a storage pipe located in front of the discard orifice is arranged between a storage pipe facing the inlet and a storage pipe facing the outlet. Heating the mechanical parts is therefore performed in the time interval allowing the ring to perform a 360 degree rotation minus two steps by means of a stepping motor for example, the inlet and outlet being separated by two steps, a first step separating the inlet and the discard orifice while another step separates the discard orifice and the outlet. Such an arrangement allows the heating time to be maximized.

The sorting method according to this embodiment will be explained below.

It is to be noted that according to the need, the number of steps may differ between the various orifices, i.e., two steps between the inlet and the discard orifice and two other steps between the discard orifice and the outlet. In fact, to be able to arrange a significant number of storage pipes on a ring in a limited space, it may be necessary to separate the various orifices by two steps instead of one.

According to another embodiment, the sorting means is deported by being arranged upstream from the conveyor pipe, i.e., between the conveyor pipe and the spring manufacturing unit. The sorting means then comprising a flexible pipe coaxial to a line for transporting mechanical parts, this sorting means is provided with an attraction means which attracts the flexible pipe to offset it in relation to the conveyor line.

Consequently, the faulty part falls in a receptacle provided to that end since it cannot enter the flexible pipe, the latter being offset. According to this embodiment, there is no discard orifice on the upstream side of the heated enclosure. The storage pipe facing the inlet is therefore also adjacent to the storage pipe facing the outlet.

According to yet another embodiment, the device does not comprise any sorting means.

In that case, if a ring comprises a plurality of storage pipes, the storage pipe facing the inlet is advantageously adjacent to the storage pipe facing the outlet. The storage pipe, once empty, will be then immediately filled in, which optimizes production rates.

According to some embodiments, the device comprises a controlling means for managing and controlling the thermal treatment device. The controlling means manages in particular the rotation speed of the ring(s), as well as the temperature of the enclosure. In addition, if a sorting means is arranged in the device and a faulty part is detected, the controlling means will request a sorting means to actuate at the desired time to eject the faulty part.

In addition, the present disclosure also relates to a method for the thermal treatment of elongated mechanical parts which may be implemented by a device according to various embodiments as previously described provided with an oven comprising a barrel arranged in a heated enclosure. According to one embodiment, the method comprises the following successive steps:

a) visually inspecting the mechanical parts so as to detect faulty mechanical parts,

b) making at least one mechanical part without defect penetrate into a storage pipe of a barrel via an inlet arranged on an upstream side of the enclosure, the storage pipe being parallel to an axis of axial symmetry of the barrel,

c) turning the barrel in a first direction around its axis of axial symmetry so that said at least one mechanical part arranged in the storage pipe is heated, and

d) the oven being provided with an outlet on the upstream side, ejecting said at least one mechanical part contained in the storage pipe from the oven when the storage pipe reaches the outlet.

This method therefore allows the thermal treatment to be optimized by thermally treating only the good mechanical parts, which saves a significant amount of time.

In addition, due to the arrangement of its inlet and outlet, it is easy to arrange the device on an existing manufacturing line. In addition, the method optimizes production rates by reducing the period of time during which a storage pipe is empty.

Advantageously, before step b), the mechanical parts are picked off so as to make them enter the storage pipe according to a predetermined sequence.

According to the first variation of the device described above, the sequence consists in making the mechanical parts penetrate one by one into a storage pipe and then proceeding with the next pipe once the storage pipe is full.

According to the second variation of the device described above, the predetermined sequence consists in storing a plurality of mechanical parts the ones after the others in a conveyor pipe in front of the inlet, then filling in, in one move, the storage pipe by sending all the mechanical parts stored at once. Once the storage pipe is full, the barrel turns to present a next storage pipe for filling.

According to a first embodiment, sorting is performed at the level of the oven. The oven being provided with a discard orifice arranged on its downstream side between the inlet and outlet of the ring concerned, the discard orifice, inlet and outlet being equidistant from the axis of symmetry, if during step a) the presence of a faulty mechanical part is detected, when this faulty part faces the inlet and the barrel comprising a plurality of storage pipes, the following steps are performed:

-   -   the barrel turns in the first direction to inject the faulty         part into the first empty storage pipe which faces the inlet,         then,     -   the faulty part is injected into the first storage pipe which         faces the inlet, and     -   the barrel turns in a second direction, opposite to the first         direction, until the first storage pipe containing the faulty         part reaches the discard orifice so as to discard the faulty         part through the discard orifice.

In some embodiments, filling in a storage pipe, which is performed during step a), simultaneously begins at the ejection phase consisting in ejecting the faulty part through the discard orifice, which optimizes the production rate. Ejection is thus performed in concurrent operation time.

According to a second embodiment, sorting is performed upstream from the conveyor pipe. If a detection means notices the presence of a faulty mechanical part, the sorting means is requested to offset a flexible pipe from the transport line so that the faulty part falls into a receptacle and does not reach the conveyor pipe.

According to a third embodiment, the mechanical parts will not be sorted.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention and its advantages will be exposed in greater details in the following description of various embodiments, in relation with, but not limited to the appended figures wherein:

FIG. 1 shows a longitudinal section of the treatment device according to one embodiment;

FIG. 2 shows a radial section of the treatment device of FIG. 1 at the level of the inlet and outlet;

FIG. 3 shows a radial section of the treatment device of FIG. 1 at the level of the barrel;

FIG. 4 shows a radial section of the treatment device of FIG. 1 at the level of the second air injection means;

FIG. 5 shows a schematic view of a sorting means according to one embodiment; and

FIG. 6 shows a schematic view of a picking means according to one embodiment.

DETAILED DESCRIPTION

FIG. 1 shows a longitudinal section of a thermal treatment device according to one embodiment.

This device is provided with an oven 20 containing a heated enclosure 22 inside which a cylinder barrel 21 able to receive elongated mechanical parts to be heated, springs for example, is arranged.

With reference to FIG. 3, the cylinder barrel 21 is provided with a first, second and third coaxial rings C1, C2, C3.

The first, second and third rings are attached to one another and are driven in rotation around the axis of axial symmetry AX1 of the barrel by being linked to a driving means 23, a stepping motor for example, via a belt 24.

It is to be noted that the number of rings may vary according to the need and being reduced to the smaller portion, i.e. a single ring. However, the use of a plurality of rings allows a single oven to be used for a plurality of manufacturing lines, which constitutes a certain advantage.

Likewise, it may be considered to dissociate the rings according to the need and in particular the heating times of the mechanical parts.

Each ring has at least one storage through pipe 25 which opens onto the downstream side F2 and the upstream side F1 of the barrel 21. The storage pipes 25 are arranged on the periphery of the rings and are parallel to the axis of symmetry AX1 of the barrel.

In addition, the device comprises a slender hollow conveyor pipe 11 shown in FIG. 6 and hidden by the ejection pipes 18 in FIG. 1, for each ring C1, C2, C3. The mechanical parts coming from their manufacturing unit are then guided by these conveyor pipes 11 toward an inlet E1, E2, E3 located on the upstream side Fl of the enclosure as shown in FIG. 2. Once they have passed through the inlet, the mechanical parts directly enter the storage pipe of the barrel facing the inlet. Transporting the mechanical parts is then performed according to a filling axis parallel to the axis of symmetry AX1.

Advantageously, with reference to FIG. 3, each ring has a plurality of storage pipes 25, each storage pipe 25 may contain a plurality of mechanical parts. The device is then able to support significant industrial production rates.

For each ring C1, C2, C3, there is therefore an inlet E1, E2, E3 and a slender hollow conveyor pipe 11.

In addition, the device comprises a slender hollow ejection pipe 18 for each ring facing an outlet S1, S2, S3 located on the upstream side F1 of the enclosure with reference to FIG. 2. It is to be noted that the inlet and outlet of a same ring are equidistant from the axis of symmetry AX1 due to the shape of the cylinder of the barrel and therefore of the rings.

At the end of their heating time, the mechanical parts exit the storage pipe of the barrel through the outlet corresponding to their ring and are ejected from the device by an ejection pipe 18 parallel to the axis of symmetry AX1 of the barrel.

The device may be implemented according to various methods.

For example, in one embodiment, a method begins during a step a), the mechanical parts are visually inspected when they exit a manufacturing unit. The inspection may be performed by a means for inspecting defects which is therefore located upstream from the conveyor pipe concerned of the device. The conveyor line separating the manufacturing unit from the conveyor pipe then comprises a section consisting of a see-through pipe, not shown in the figures, through which the visual detection means, a camera for example, inspects the mechanical parts being transported.

During a step b) which follows step a), a means for controlling the device makes one or more mechanical parts without defects enter a first storage pipe 25 via an inlet E1, E2, E3.

It is to be noted that a first air injection means blows in the conveyor line so as to push the mechanical parts into the storage pipe.

Once the first storage pipe 25 is full, during a step c), the controlling means make the ring of the barrel turn in a first direction around the axis of symmetry AX1.

A second empty storage pipe then facing the inlet, the controlling means repeats the previous step to fill it in. Meanwhile, the mechanical parts contained in the first storage pipe are heated.

When the first storage pipe reaches the outlet, after a 300° rotation if reference is made to the schematic view of the figures, the mechanical parts are ejected from the first storage pipe. Then, with reference to FIG. 4, the device comprises a second air injection means 44, 45, 46 which blows air into the storage pipe, via the downstream side F2 of the heating enclosure opposite to the upstream side F1, to push the mechanical parts through the outlet and the ejection pipe so as to direct them toward a packaging unit for example.

In addition, so as to perfectly control the transport of mechanical parts toward the inlet, during an intermediate step previous to step b), the mechanical parts are picked off to enter the storage pipes 25 according to a predetermined sequence using a picking means 10.

For each conveyor pipe 11, the picking means comprises a downstream electromagnet 14 and an upstream electromagnet 15. The upstream electromagnet 15 is fixed while the downstream electromagnet 14 is mobile according to an axis parallel to the axis of symmetry AX1 so as to authorize a local setting according to the length of mechanical parts.

In addition, each electromagnet activates a blocking means which goes across the conveyor pipe to block the mechanical parts or let them pass, a retractable needle or strip able to go across a spring to block it for example. Both electromagnets of a pipe operate alternately, an electromagnet being in the blocking position while the other electromagnet is in the open position and let the mechanical parts pass.

According to a first variation, filling in is performed by unit. First, the downstream electromagnet 14 is in the blocking position while the upstream electromagnet 15 is open and let a mechanical part pass.

Then, the upstream electromagnet 15 switches in the blocking position and prevents the other mechanical parts from moving in the conveyor pipe. On the contrary, the downstream electromagnet 14 is put in the open position, which allows the mechanical part to enter the storage pipe.

This operation is repeated until the storage pipe is full. At this stage, the controlling means makes the ring(s) of the barrel turn, using the driving means, to present a new storage pipe 25 in front of the filling orifice so as to continue the filling sequence.

According to a second variation, the controlling means performs filling by batch. For this variation, the space separating the upstream electromagnet from the downstream electromagnet corresponds to the length of the filling pipes.

First, the downstream electromagnet 14 is in the blocking position while the upstream electromagnet 15 is open and let all the mechanical parts that must enter the filling pipe pass.

Then, the upstream electromagnet 15 switches in the blocking position and prevents the other mechanical parts from moving in the conveyor pipe. On the contrary, the downstream electromagnet 14 is put in the open position, which allows the storage pipe to be filled in one move by letting all the mechanical parts pass into the storage pipe at once.

Then, the controlling means makes the barrel turn, using the driving means, to present a new storage pipe 25 in front of the filling orifice so as to continue the filling sequence.

In addition, according to a first and second embodiments, the device comprises a sorting means preventing the thermal treatment of the faulty parts detected during step a).

According to a first embodiment, the sorting means comprises a discard orifice R1, R2, R3 for each ring, shown in FIG. 2, arranged on the upstream side F1 of the heated enclosure 22 between the inlet E1, E2, E3 and outlet S1, S2, S3, the inlet E1, E2, E3, and outlet S1, S2, S3 and discard orifice R1, R2, R3 of a ring being equidistant from the axis of symmetry AX1.

In addition, with reference to FIG. 4, the device comprises a complementary air injection means 41, 42, 43 for each ring, on the downstream side F2 of the enclosure to eject a faulty mechanical part from a storage pipe though the discard orifice.

This first embodiment is advantageously combined to the first picking variation described above.

When the controlling means detects a faulty mechanical part, it blocks it just before the inlet of the enclosure and does not make it enter a first storage pipe being filled in.

Then, the controlling means makes the ring of the barrel turn in a first direction to present a second empty storage pipe, and injects the faulty part into this pipe.

Then, the controlling means makes the barrel turn in a second direction, opposite to the first direction, to position the second storage pipe in front of the discard orifice and position the first storage pipe being filled in front of the filling orifice.

Filling in the first pipe may then be resumed. In parallel, the first controlling means activates the complementary ejection means to make the faulty part go out through the discard orifice.

FIG. 5 shows a second embodiment. The manufacturing unit 50 sends the mechanical parts toward the heated enclosure 22 of the treatment device.

The sorting means is then deported and comprises a flexible pipe 52 arranged on the conveyor line 51. If a mechanical part is faulty, the controlling means activates an attraction means, an electromagnet 53 for example, so as to offset the flexible pipe 52 in relation to the conveyor line 51. The faulty mechanical part may then not pass through the flexible pipe and falls according to the arrow F into a receptacle 54 provided to that end.

The various embodiments described above are susceptible of various variations regarding the implementation thereof and can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure. 

1. A device for the thermal treatment of elongated mechanical parts, comprising: an oven having a barrel arranged into a heated enclosure, the barrel including a ring driven in rotation around an axis of axial symmetry of the barrel by a driving mechanism, the ring having at least one storage pipe parallel to the axis of axial symmetry, and the enclosure having an inlet and an outlet corresponding to the ring equidistant from the axis of axial symmetry of the barrel; a conveyor pipe for guiding the mechanical parts toward the storage pipe of the ring via the inlet and along a filling axis parallel to the axis of axial symmetry; and an ejection pipe for guiding the mechanical parts when the mechanical parts exit the storage pipe of the barrel through the outlet after a rotation of the barrel, the inlet and outlet being arranged on an upstream side of the enclosure.
 2. The device of claim 1, wherein the oven includes a plurality of coaxial rings, and the device further comprises a plurality of conveyor pipes respectively corresponding to the coaxial rings and a plurality of ejection pipes respectively corresponding to the coaxial rings, the conveyor and ejection pipes being arranged on the upstream side of the enclosure.
 3. The device of claim 1, further comprising: a first air injection system positioned to push mechanical parts from the conveyor pipe toward the storage pipe.
 4. The device of claim 3, further comprising: a second air injection system positioned to push mechanical parts from the storage pipe toward the first ejection pipe, the second air injection system being arranged on a downstream side of the enclosure, opposite the upstream side.
 5. The device of claim 1, further comprising: a picking system configured to sequentially fill the storage pipe.
 6. The device of claim 5, wherein the picking system includes two electromagnets, arranged on the conveyor pipe, which operate alternately.
 7. The device of claim 1, further comprising: a sorting system configured so as not to thermally treat faulty mechanical parts.
 8. The device of claim 7, wherein the sorting system is arranged upstream from the conveyor pipe, the sorting system having a flexible pipe coaxial to a conveyor line of the mechanical parts and an attraction mechanism configured to selectively attract the flexible pipe to offset it in relation to the conveyor line.
 9. The device of claim 7, wherein the oven includes a plurality of coaxial rings and the sorting system includes a discard orifice for each ring arranged on the upstream side of the enclosure between an inlet and an outlet of each ring, the discard orifice, inlet and outlet of each ring being equidistant from the axis of axial symmetry.
 10. The device of claim 9, further comprising: a complementary air injection system for ejecting a faulty mechanical part through a respective discard orifice, the complementary air injection system being arranged on a downstream side of the enclosure, opposite the upstream side.
 11. The device of claim 9, further comprising: a controlling system for managing and controlling the device.
 12. The device of claim 9, further comprising: a visual detection system for visually detecting faults of a mechanical part upstream from the conveyor pipe.
 13. A method for the thermal treatment of mechanical parts, the method comprising: visually inspecting the mechanical parts to detect faulty mechanical parts; making a plurality of mechanical parts without defect penetrate into a storage pipe of a barrel arranged in an enclosure via an inlet arranged on an upstream side of the enclosure, the storage pipe being parallel to an axis of axial symmetry of the barrel; rotating the barrel in a first direction around its axis of axial symmetry so that the mechanical parts arranged in the storage pipe are heated; and ejecting the mechanical parts contained in the storage pipe from the oven when the storage pipe reaches an outlet located on the upstream side of the enclosure.
 14. The method of claim 13, wherein making a plurality of mechanical parts without defect penetrate into a storage pipe includes making a plurality of mechanical parts without defect penetrate into the storage pipe according to a predetermined sequence.
 15. The method of claim 14, wherein the predetermined sequence consists in storing a plurality of mechanical parts in a conveyor pipe in front of the inlet and then filling the storage pipe by sending all the mechanical parts stored in the conveyor pipe at once.
 16. The method of claim 13, wherein the oven includes a respective discard orifice arranged on the upstream side of the enclosure between the inlet and outlet of each ring, the discard orifice, inlet and outlet of each ring being equidistant from the axis of symmetry, and wherein the method further comprises turning the barrel, when a faulty mechanical part is detected, in a first direction to align the faulty part with a first storage pipe which faces the inlet, injecting the faulty part into the first storage pipe which faces the inlet, and turning the barrel in a second direction, opposite to the first direction, until the first storage pipe containing the faulty part aligns with the discard orifice. 